System Description	Temperature Range(K)	Other Capabilities	Available Instruments
Pulse Tube CCR	4 - 325	Low Vibration	BT-1
Low Temp. CCR	5 - 325		All
Top Loading CCR	5 - 600	Gas Handling, High Pressure	All
General Use CCR	10 - 325	Gas Handling	All
Low Temp. CCR w/Tail Extension	10 - 325	Electromagnet Mountable	NG-1
High Temp. CCR	30 - 600	High Voltage(6KV)	All

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General CCR Information

How They Work

• Our CCRs, excluding the pulse tube CCR, use the Gifford-McMahon Refrigeration Scheme
  • Helium gas is the refrigerant
  • The gas compressor (operating near room temperature) and the cryogenic expansion cylinder (cold head) are thermally linked by a regenerator or thermal storage device
  • The gas is driven through the 4-step cycle shown below

Setup

Many of the different items that make up the CCR systems are standard and interchangable among the different systems, somtimes even the different types of systems. These items include the sample block, heat shield cans, temperature controller, sensor and heater cables and vacuum can. New systems are generally bought to conform to the standard setup to make integration easier. This also makes going in-between the different systems easier for experienced and novice users. Another important aspect of a CCR system are PID parameters. These parameters vary depending on the setup of each type of CCR and sometimes even on the exact system in use.

• Temperature Sensors

  As mentioned above, tempeature sensors are a standard item in the CCR systems. There are only two types of standard sensors used. The first, silicon diode, is the most common and is used for low temperature measurements. The seconed, platinum resistor, is used for high temperature measurements. In a few cases thermocouples are also used, but they are exceptions. Temperature sensor information for individual systems is available in the booklet attached to each system. This information includes the type, temperature range, corresponding controller curve and physical location. Be sure to verify this information before starting the system.

• Temperature Controllers

  These are another standard piece of the CCR system. We use Lakeshore 340 or 331 controllers on all of the systems and they also use identical cabling. This allows us to easily diagnose problems and have plenty of spare parts on hand. The difference between the two controllers is mainly that the 340 can supply 2amps of heater output and the 331 can supply only 1amp. For this reason the 340s are used on all of the high temperature systems which require more heater power. Be sure to verify that all sensors are reading at room temperature and contact a sample environment team member if you have problems.

• Sample Space and Sample Mounting

  • CCR Sample Space Drawing
  • Sample Mounting Info Page
  
  

• PID Parameters

  In general PID parameters should be determined and loaded into the controller before a CCR system is put into service. However, sometimes parameters get changed by users and are not returned to the standard values. Double check that PID values are correct by comparing those stored in the controller with those in the system manual and on the PID webpage.
  Note: In addition we are in the process of determining PIDs for individual systems in a new manner. The systems that have the new PIDs are listed below.

  • Top Loading CCR (pdf will open in new window)
  • CCR-11 (pdf will open in new window)
  • CCR-13 (pdf will open in new window)
  • CCR-14 (pdf will open in new window)
  • CCR-H02 (pdf will open in new window)
  • CCR-H03 (pdf will open in new window)

  These new PID values take advantage of a feature called a PID zone table. Below you will find a link to a one page manual on how to load a PID zone table.

  • How to Load a PID Zone Table (pdf will open in new window)

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